Inverters Features an Improved Sensor-less Vector Control Algorithm
Hitachi America, Ltd., Industrial Systems Division, introduces the SJ700 Series of inverters. The SJ700 expands on the performance, capabilities and functions of its predecessor, the SJ300.
Hitachi's SJ700 features an improved sensor-less vector (SLV) control algorithm that enables the SJ700 to develop more than 200% starting torque at 0.3 Hz. The SJ700 can develop 150% torque at 0 Hz. Hitachi has also simplified the auto-tuning process, making commissioning trouble-free.
Another enhancement in the SJ700 is Hitachi’s EzSQ (Easy Sequence) built-in programming function. In many cases, the need for a separate PLC can be eliminated. The program is developed on a PC and then downloaded to the inverter using the EzSQ software provided at no charge.
The SJ700 also incorporates true servo-like position control, offering a low-cost motion control solution. Mated with a general-purpose induction motor with an encoder, the SJ700 is given a position command, speed command and acceleration/deceleration times. The shaft will move from position A to position B following the defined profile and then maintain the shaft in servo lock status.
The SJ700 offers several new features, including micro-surge voltage suppression (to protect the motor winding insulation), advance trip avoidance functions, configurable sink/source logic on I/O, built-in dynamic braking circuit in models up to 30 hp (22 kW) and built-in EMC filter up to 75 hp (55 kW).
The SJ700 also includes anticipated features, such as built-in RS485 Modbus/RTU communication and options for other communications networks, such as Ethernet Modbus/TCP, DeviceNet, Profibus and LonWorks. The SJ700 can be configured via the front-mounted keypad or using Hitachi’s ProDrive PC-based software. The SJ700 carries CE, UL, cUL and c-Tick marks and is RoHS compliant.